Improvement in molds for vulcanizing rubber



- H. A. ALDEN.

Vulcni-zing Apparatus, No. 41,347. Patented Jan. 19, 1864.

UNITED STATES HENRY A. ALDEN, OF MATTEAWAN,

PATENT ()FFICE NEW YORK, ASSIGNOR To THE NEW YORK RUBBER COMPANY.

IMPROVEMENT IN MOLDS FOR- VULCANIZING RUBBER, 81 0;

Specification forming part of Letters Patent No. 4 l .347, dated January 19, 1864.-

To aZZ whom it may concern):

Be it known that I, HENRY A. ALDEN, of Matteawan, in-the county of Dutchess and State of New York, have invented a new and useful Improvement in Molds for Vulcanizing India-Rubber and other Similar Gums; and I hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, in which the several figures represent in isometrical perspective view and in longitudinal and transverse sections the parts constitutin g the mold and the coutrivances used in producing it.

A large proportion of india-rubber articles are produced in molds. Toys and many other objects made hollow or of a spongy consistenoy or having their surfaces ornamented by designs or figures in relief are all of necessitymade in molds. To carry on this art on a manufacturing scale, it was necessary to reproduce themolds in a cheap way. The plan generally adopted consisted in making a pattern of brass or other fine-textured and hard metal, from which the molds were cast of type metal-21 0., a composition of lead and anti- 1nony-being an alloy which, although fusible at a comparatively low temperature, will resist the vulcanizing-heat and take a most perfect cast.

In Figure 1 I have shown such a pattern, being that of one-half of a mold for babys rattle. This pattern A is elaborately engraved or worked, presenting the design or figures delineated in the highest style of art. The plane surfaces are carefully planed and polished, so that the molds when cast shall have their faces equally well polished to produce a perfect fit. In connection with this pattern, a, frame, B, made of brass or other resisting material, is used. This frame forms a tightly-fittin g ridge around the pattern A, to which it is adjusted by means of pins or other means of adjustment, so that the type metal, which is poured into the fame through its opening at 0, shall be retained within the interior of the frame, there to congeal, taking cast of the pattern.

When the type metal is solidified and cold, the frame B is taken off the pattern by means of the handle D, and the mold formed Within the frame of type metal is dropped or knocked out. The other half of the mold is similarly made, and the two halves constitute one of the soft-metal molds which have been in use for many years. Although the reproduction of molds in a cheap way was a great step in advance, yet there were serious difliculties to contend against. Thus, by repeated use the molds, exposed as they were to a high temperature and under pressure, (for the molds are firmly clamped -by means of wedges while undergoing the process of vulcanization,) would become disfiguredi, 0., they would yield under the'pressure that holds them to gether and become flat. When the molds thus get out of shape, they cannot be used for any purpose, and have to be thrown away, and the loss thereby sustained is very consid erable.

To remedy this evil is the object of my invention, and I have accomplished it by the employment of a cast-iron shell of a peculiar construction,so that, while giving to the mold the rigidity whereby combined pressure and heat cannot aifect it, it will also reduce the amount of type metal used to a minimum without thereby interfering with the accuracy and perfection of the cast upon all exposed sides.

To enable others skilled in the art to make and use my improvement, I shall now proceed to describe the construction and the man ner of operation of my new mold.

Fig. 3 represents the cast-iron shell used in connection with the pattern and frame hereinbefore referred to, and constituting the essential feature of this invention. It is roughly: cast, therefore cheaply made, of such general form that it will fill the space within the frame and pattern (when the two are properly adj Listed) without, however, touching any part of the pattern proper-4'. 0., any of the engraved, planed, or polished surfacesof which it is desired to produce a cast to form the vulcanizing-mold.

The figure shows the cast-iron shell reversed, so as to expose to view the interiorthat is to say, the parts corresponding to the ball, handle, and ring of the rattle, also the joint surface. On each end there is a supporting-standard or set-off projecting below, (in the drawings above,) the surface facing the joint surface, the object being to hold the shell in such position in the frame as that a slight space shall be maintained above the said joint surface, and so that the type metal poured into the molds shall flow into this reserved space and take a cast of the surface, along which the upper and lower shells of the mold are united and fitted with utmost accuracy.

The iron shell is shown perforated on top, an opening being provided corresponding with that in the frame, through which the metal is poured and made to penetrate into the shell. The shell being placed onto the pattern, it is adjusted by the setting of the frame. It is then firmly held in position and ready to receive the metal.

in Figs. 4, 5, and (5 I have shown the pattern, shell, and frame properly united, 1t indicating the type metal.

When the cast is formed, the mold is made and removed from theframe. The mold then consists of an iron shell, with a thin lining of type metal, in which ornamented figures and plane or round surfaces are truly impressed. These moldswhen in use are n otliable to flatten, atiord a great saving'in type metal, and pro duce fine impressions, necessitating no planing, smoothing, or other finishing operation.

Having now fully described my invention and the manner in which thesame is or may be carried into effect, I claim 1. The method oflining eastiron molds with type metal or other comparatively soft and fusible metal, by the em nloyment, in combination with a pattern and cast-iron mold, of a frame constructed to eadily adjust and firmly hold the mold in place during; the process of forming thelining', at the same time confining the fusible metal, substantially as shown and described.

2. The construction of the cast-iron mold so as to allow of the joining surfaces of the mold being cast of soft metal, substantially as set forth and shown.

In testimony whereof I have signed my name to this specification before two subscribing witnesses.

I n. A. ALDEN.

Witnesses:

F. E. OLIVER, A. PoLLAK. 

